var EXTLIB = Ext.lib,
        noNegatives = /width|height|opacity|padding/i,
        offsetAttribute = /^((width|height)|(top|left))$/,
        defaultUnit = /width|height|top$|bottom$|left$|right$/i,
        offsetUnit =  /\d+(em|%|en|ex|pt|in|cm|mm|pc)$/i,